Inspectors from the city Health Department found Rhodamine B, an industrial dye prohibited from being used in foods in Vietnam, in melon seed samples taken at the Nguyen Hung household factory on Hau Giang Street, District 6.

The dye content was 1.19 milligrams per kilogram. Seed roasters have been known to use the dye to brighten the red color of the seeds.

Nguyen Thi Huynh Mai, an inspector, said Nguyen Hung produced melon seeds on a small scale and only upon order from market vendors.

A representative from Nguyen Hung on Tuesday said the contaminated sample was taken from their first batch of the Tet (Lunar New Year) holiday. One third of the 30-kilo batch had been sold before the inspection, according to the representative.

The factory has been suspended and forced to dispose of the rest of the batch.

Company owner Mai Nguyen Hung will be fined VND10-15 million (US$541-812) for using the banned chemical.

In December, health authorities in the central city of Da Nang also found Rhodamine B-soaked melon seeds at a local firm.

Roasted melon seeds are seen on most Vietnamese tables during Tet celebrations as their red color represents luck and the sound of the seeds cracking between teeth is considered auspicious.